1. Field of the Invention
The present invention relates to a bucket for a work vehicle, and to a work vehicle equipped with such a bucket.
2. Background Art
Japanese Laid-Open Patent Publication 2001-32318 discloses a spill guard that reduces spillover of the bucket load, while still ensuring the visibility of its upper end portions while the vehicle is traveling. The shape of this spill guard is determined in the following manner. First the points of intersection between a surface defining the spill guard and a line connecting the upper end portions and a point of view (an eye point) that is determined in advance. The shape of the spill guard is determined so that at least these points of intersection are cut out.
The objective of the design of the spill guard according to Japanese Laid-Open Patent Publication 2001-32318 is to secure the visibility of at least the end portion of the bucket during traveling of the vehicle, i.e. in the state that the boom is lowered, as well as to reduce, to the greatest possible extent, spillover of the bucket load, in which portions of the load stuff in the bucket fall down from the bucket. Accordingly, the spill guard is designed to be cut out as little as possible, except for its end portions.
However, it is not sufficient only to secure the visibility of the end portions of the bucket. For example, because the bucket is held up to be higher than the cab when the work vehicle loads the load stuff into a truck, it is desirable for the spill guard to be cut out to such an extent that it is possible visually to check the load stuff in the bucket even when the bucket is thus being held up. In other words, it is desirable for it to be cut out to the extent that it is also possible visually to check the portions of the bucket that are nearer to its center. However, there is no investigation related to this type of problem in Japanese Laid-Open Patent Publication 2001-32318.
Moreover, when the spill guard is cut out to such an extent that it is possible visually to check the load stuff in the bucket even when the bucket is raised up, then, when a great deal of stuff is loaded into the bucket, some portion of this load stuff may fall down from the bucket. However it is not desirable for the load stuff to fall down upon the couplings of the left and right booms and the tilt rod that support the bucket, because it deteriorates the rotation performance of these couplings. Moreover, when the cutout in the spill guard is large, then it becomes highly possible that the load stuff falling down from the bucket may slide along the boom and collide with the front glass of the cab, and thereby damage the front glass.